Bimetallic thermal strips comprised of two metals having dissimilar thermal expansion rates are well known and are used in various temperature actuated devices such as thermostats and circuit breakers. The principle by which such bimetallic strips operate depends upon the dissimilar rates of thermal expansion of the two materials. The strip bends toward the material having the lower rate of thermal expansion when the strip is heated. Alternatively, the strip bends toward the material having the higher rate of the expansion when the strip is cooled.
Similarly, the principle of magnetostriction relates to the expansion which a magnetostrictive material undergoes when subjected to a magnetic field. Bimetallic magnetostrictive strips operate on a principle similar to bimetallic thermal strips. Bimetallic magnetostrictive strips have been used heretofore and are shown in U.S. Pat. No. 2,475,148 issued on July 5, 1949 to F. Massa for TRANSDUCER MEANS, U.S. Pat. No. 2,764,647 issued on July 25, 1956 to W. G. Leslie et al for a MAGNETOSTRICTIVE RELAY, and in U.S. Pat. No. 3,216,131 issued on Nov. 9, 1965 to J. Singerman for a MAGNETOSTRICTION TEACHING DEVICE. The construction and operation of magnetostrictive strips is further shown and explained in these patents. However, the utility of a magnetostrictive strip as a closure device has not heretofore been recognized.